The field of this disclosure relates to magnetic resonance imaging (“MRI”) systems. More particularly, the disclosure relates to a system, method and apparatus for minimizing operator intervention during the process of tuning a radio-frequency (RF) coil of an MRI.
MRI is a diagnostic imaging modality that does not rely on ionizing radiation. Instead, it uses strong (ideally) static magnetic fields, RF pulses of energy and magnetic field gradient waveforms. An RF coil produces the RF pulses. MRI is a non-invasive procedure that uses nuclear magnetization and radio waves for producing internal pictures of a subject. Three-dimensional diagnostic image data is acquired for respective “slices” of an area of the subject under investigation. These slices of data typically provide structural detail having a resolution of one (1) millimeter or better.
When utilizing MRI to produce an image, a technique is employed to obtain MRI signals from specific locations in the subject. Typically, a region that is to be imaged or region of interest (ROI) is scanned by a sequence of MRI measurement cycles, which vary according to the particular localization method being used. The resulting set of received MRI signals are digitized and processed to reconstruct the image using one of many well-known reconstruction techniques. To perform such a scan, it is, of course, necessary to elicit MRI signals from specific locations in the subject. This is accomplished by employing gradient magnetic fields. By controlling the strength of these gradients during each MRI cycle, the spatial distribution of spin excitation can be controlled and the location of the resulting MRI signals can be identified.
An MRI system requires not only an intensive uniform magnetic field generator, but also a suite of associated electronics to operate the MRI system. In order to assure accuracy of images obtained by the MRI system, a typical MRI system requires tuning of the RF coil prior to use. RF coil tuning often requires operator intervention to ensure proper tuning between scans. Operator intervention increases the time of the tuning process and may introduce errors into subsequent measurements made by an improperly tuned RF coil. Additionally, insertion of metallic objects into the RF coil often distorts measurements, which can invalidate the RF coil tuning. Thus, it is desirable to develop a method and apparatus capable of acquiring RF measurements without introducing the drawbacks described above.